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The productivity of alfalfa as related to management

Graber, L.F., Sprague, V.G.
Agronomy journal 1938 v.30 no.1 pp. 38-54
Medicago sativa, crop yield, crop management, cutting, residual effects, soil fertility, rain, cold injury, mortality, Empoasca fabae, insect pests, frequency, Wisconsin
Alfalfa is very sensitive in its response to managerial treatment under the environmental conditions of southern Wisconsin. The total production of oven-dried, weed-free alfalfa hay during the 4-year Period (1931-1934) of this trial varied from 13.29 tons to 5.98 tons per acre in accordance with management. The productivity and duration of Canadian variegated alfalfa was compared under favorable conditions of management, including the maintenance of an optimum level of fertility, ample summer and fall storage of food reserves, abundant vegetative winter cover, and the absence of leafhopper damage, with the alternatives of moderately low fertility, early cutting of the first growth and leafhopper injury, reduced winter cover and reduced fall and summer storage of food reserves. The responses of alfalfa to various combinations of such favorable factors and unfavorable stresses were measured on the basis of productivity and survival. It was not possible to differentiate fully the degree to which each factor of management influenced the productivity or duration of the alfalfa, but their interactions could be quite clearly approximated. Cutting treatments not only affected the immediate productivity of alfalfa but also subsequent productivity and survival. Such residual influences were very significant in this trial. All fall cutting treatments proved harmful in this experiment, but late fall cutting after maximum food storage bad occurred was definitely less detrimental with respect to productivity and survival than fall cuttings which not only reduced vegetative cover but also autumnal storage of reserve foods. An optimum level of fertility greatly increased the productivity and duration of alfalfa when compared with that grown on soil moderately low in fertility. This held true whether the cutting treatments were favorable or unfavorable with respect to root storage, winter cover. and leafhopper damage. Twelve days earlier cutting of the first growth in 1932 and 1933 greatly lowered the immediate and subsequent productivity and the survival of alfalfa. It depressed the productivity of the first growth, particularly, of alfalfa which had suffered winter injuries induced by previous fall cutting treatments. It resulted in very severe infestations of leafhoppers, which caused heavy losses in the productivity of the second growth and such losses were most pronounced when alfalfa had undergone winter injury induced by previous fall cutting treatments. The residual effects of the various cutting treatments applied to alfalfa in 1931, 1932, and 1933 were reflected, clearly and definitely, productivity of alfalfa in 1934.